I'm not guilty, says Charles - whatever the charge

In perhaps the most bizarre turn yet for the scandal-plagued royal family, the heir to the throne has denied being involved in an "incident" that has been hinted at - but never revealed - in the British press.

"I just want to make it entirely clear, even though I can't refer to the specifics of the allegation, that it's totally untrue and without a shred of substance," the prince's private secretary, Sir Michael Peat, said in televised remarks on Thursday.

"It is risible. It is totally untrue. Although having said that, even allegations which are untrue can cause distress, great distress."

The denial was apparently an attempt to kill off the mystery scandal, but it has fuelled public curiosity as to just what it was that the prince says he did not do.

For months several newspapers have said Britain's tough libel laws have prevented them from publishing the details of the supposed scandal, but that if the public knew the story it could bring down the monarchy.

A former aide to Prince Charles, Michael Fawcett, made use of those laws to win a court order against the Mail on Sunday tabloid this week to prevent it printing a story the paper said concerned "matters of the deepest public interest".

Another newspaper added to the pressure on Thursday by winning the right to publish that it was Mr Fawcett who had obtained the injunction against the Mail on Sunday.

Mr Fawcett has argued that publication of the Mail's story would seriously libel him. Until Thursday, the royal family refused to comment, while speculation and innuendo continued unrelentingly in the media as to just what the story might be.

In its denial, the prince's office filled in some of the holes. After The Guardian named Mr Fawcett on its website, his office issued a statement. "In recent days there have been media reports concerning an allegation that a former royal household employee witnessed an incident some years ago involving a senior member of the royal family," it said.

"The speculation needs to be brought to an end. The allegation was that the Prince of Wales was involved in the incident. This allegation is untrue.

"The incident which the former employee claims to have witnessed did not take place."

In March Mr Fawcett resigned as Prince Charles' aide after an inquiry into a series of royal scandals found members of the prince's staff guilty of "serious failings". Mr Fawcett resigned even though the inquiry, ordered by the prince, cleared him of financial impropriety - selling royal gifts for cash.

The royal biographer Una Mary Parker said the decision by the royal family to come forward and deny the mystery allegation was a change of tack for the palace.

"They have been accused of being like ostriches and putting their heads in the sand. But I think if you're going to make a statement you've got to go all the way and make a full statement. Because people are not even sure what the allegations are. It's confusing to the general public."